2005年10月 紙パ技協誌

[プリント用ページ]

Advanced Screening Concepts

Andreas Sauer and Naoyuki Iwashige
Application Engineering Dept., Voith IHI Paper Technology Co., Ltd.

 Screening is a decisive process stage for removing contaminants from fiber pulp. Different tools are necessary for different kind of tasks. It starts with the question “what should be screened" -primary or secondary fibers (brown or white) and “what contaminants" like coarse, fine disturbing components or shives or stickies. For each screening task, different kinds of screens are necessary. But what are the big influences on quality and what kind of impact do they have on a screen? It is common to discuss hole sizes and slot width. But beyond that discussion, several other points have to be taken into account.
 In Europe new advanced screening concepts have been developed recently. The new concepts are using “Tandem Systems" with Feed Forward. Beyond that Intermediate Screening are used instead of Middle Consistency Screening Systems. Therefore a high variety of pre/ and fine screening arrangements are in operation in DIP Systems. They always compromises between maximum cleanliness efficiency, minimal fiber losses and investment costs. This presentation pick up some of the most advanced combinations and investigates the investment costs and performances. Due to the development of the new LP Screen new concepts for the OCC Line are also introduced.


Forerunner for Next Generation Canvas Cleaner

Akiyoshi Shibata
Canvas cleaner-project KGK Engineering Group

 With ever increasing use of recycled papers, the maintenance of a stable quality of papers is the hot issue the paper industry is facing right now. Several issues are related in this regard. However, keeping dryer canvases clean is one of the on going hot issues.
The methods of dryer canvas cleaning is very diversified, such as from shower cleaning methods with lots of clean water consumption, to traversing cleaning head systems between FS and BS to get the benefit of all-over cleaning. However, none of them has ever reached the level of total completion.
 We enjoy a very experienced history over handling canvas cleaner systems as the very first company ever introduced the canvas cleaner system into the PPI industry in Japan. The machine speed has achieved a surprise increase from 800m/min level of 1970 to 2000m/min level of the present. This has made possible with the paper machine development from fourdrinier former, to on-top former and further to gap formers(with better effect of no-draw). Together with it, the machine width has increased remarkably.
 With this ever increasing machine speed and widening machine width, the hiking usage of recycled paper has ever spot lighted the issue of dirty dryer canvases which works very bad to deteriorate the paper quality.


Mono-screw Pump which is Advantage in View of Maintenance
- Mono-screw Pump which is Long Interval Time between Maintenance and Easy Disassembling
  and Reassembling -

Yoshiro Tsuruga
ENGINEERING DIV., IWAKI CO., LTD.

 Mono-screw pump is well known. The most important feature of the mono-screw pump introduced here is double shaft construction of five year guaranteed flexishaft and pump shaft. This construction enables long interval between maintenance and easy disassembling and reassembling at the time of maintenance and inspection.
 In addition to above mentioned feature, another feature is the long life for whole pump because the user can select suitable coating of rotor according to pumped liquid and because reliable mechanical seal is employed in cooperation with mechanical seal manufacturer. Most of users of this pump do not do the maintenance works except replacement of rotor and stator.
 Generally used pin joint or gear joint needs periodical maintenance works, above all, qualified worker is needed to disassemble and reassemble the gear joint.
Mono pump does not need qualified person to be disassembled and reassembled, and inside company person can do the maintenance works for small size to large size pump. Furthermore, interval time between maintenance for whole pump can be shortened by selecting suitable parts, which saves the cost for maintenance such as spare parts cost and personnel expenses.


Study of Less-dirt Parts for Paper Machines

Junji Taguchi, Norio Fujita and Keiji Nakai
Nomura Plating Co., Ltd.
Yong-Bo Chong
Research Institute for Applied Science

 In recent years, rolls contaminated easily during the machine operation causes serious defects on paper.
 It was found out that an excellent plating with the hydrophobicity and durability .It was superior to fluoroethylen resin that is hard to be contaminated, as a result.
 It was found to improve the coating paper quality by appling a metering rod for a coater machine on paper machine’s equipment. On the other hand, it will be applied the cover of various rolls for easy relies contaminant.


Papermakers Experience with Improved Talcs for Pitch and Stickies Control in Europe and North America

Shingo Hayakawa
Nihon Mistron Co., Ltd.
J. Yordan, V. Lasmarias, P. Biza and G. Williams
Luzenac Group

 Modern papermaking requires modern additives, especially with the growing importance of environmental protection, the need to improve cost efficiency and safe product handling. Talc is the natural product for the paper industry with three main properties, hydrophobic/organophilic surface, softness and platy structure. Most talc applications are based on the improved quality or reduced cost talc offers to the end users. The fact that talc is chemically inert makes it safe for handling and application as well as an environmental friendly product.
 In this paper the experience with novel surface-treated talcs in six European, North and South America paper mills is presented. More specifically, there experiences describe the successful control of pitch and stickies obtained with two types of surface-treated talcs at four newsprint mills, a fine paper mill and mechanical (TMP and groundwood) and recycled pulps or combinations thereof.


Development of New Pigment which Gives High Opacity

Motoshi Tamura, Noriaki Matsuda and Kazuyuki Hosoi
SHIRAISHI KOGYO KAISHA, LTD.

 In the paper manufacture industry, precipitated calcium carbonate (PCC) and titanium dioxide (TiO2) have been widely used as a filler in order to improve whiteness and opacity of paper for many years. TiO2 is an expensive product and has a problem, which is low one-pass retention in paper making process compared with PCC.
 Recently, the composite of TiO2 and PCC has been researched by various methods in order to improve retention and optical properties such as opacity and brightness.
“Valkofil” is our new Pigment combined with TiO2 and PCC using our unique process. Valkofil is able to give higher opacity and Light Scattering coefficient (L.S.C) to paper than conventional PCC.


Stabilized Bromine - A New Technology for Alkaline Microbiological Control

Gray W Johnson
Nalco Pacific Pte Ltd., Singapore

 The global movement to neutral-alkaline papermaking has increased pressure on microbiological control in the wet end. Over the past decade, in an effort to improve program effectiveness and to reduce costs, the widespread utilization of halogenated oxidizing biocides has brought with it additional operational problems such as increased corrosion, chemical attack of other wet end additives and paper machine clothing, and increasing environmental concerns about the discharge of AOX. A new stabilized bromine based biocide that releases halogen slowly has demonstrated; both rapid kill and persistency; compatibility with other additives, reduced corrosion, and has the potential to reduce the dosage of other more harmful biocides.


Advanced Winder Adviser Controlling to a Winder Operation

Atsushi Kurosaki
Cognex K. K.

 The results of Advanced Winder Advisor (AWA) system are highlighted. AWA can control to a winder accurately, using inspection data and synchronization by SmartView Paper web Inspection system. The results are (1) Stopping at desired defects within ±10 cm, (2) Reduce winder operation time.
 SmartView and Advanced Winder Advisor package allow users to have best performance of inspection and winder operation.


“Visualization of Operations” and “Integration of Operation Environment”
-OperationAnywhere-

Manabu Doji and Yutaka Makino
Advanced Automation Company・Yamatake Corporation

 Since introduction of Distributed Control System (DCS), plant and process controls are automated and operations became central controls. However there are a lot of field operations as ever for various reasons. In the situation operators of baby-boom generation who play a key role in the field are ageing. It is certain that generational shift from experienced operators to younger proceeds. It is a critical issue that next generation takes over the know-how of experienced operators in order to maintain safety and stable plant operations.
 Because of the central control architecture of traditional DCS, the functions were not sufficient to assist in field operations. Then Yamatake offers “OperationAnywhere” as a new generation concept that realizes Operations freely without restrictions of space. “The visualization of operations” means to catch the field conditions from office or remote place and the producing status of whole plant include other process. “The Integration of operating environments” means to operate of separate systems at the same time through the single Windows terminal and to minimize costs for the investment as compared with before.
 We introduce the detail of concept “OperationAnywhere” and that product family.


Experience with Modern RCF Line Producing Stock for Industrial Grades

Kimmo Nurminen
Andritz Oy
Yousuke Takeshita
Andritz K.K.

 The environmental and economic benefits of using recycled raw materials are becoming increasingly self-evident to many different industries. For this reason a growing number of paper and board manufacturers globally are now favoring recovered fibers as raw materials. And as the recovery rate increases, the use of recovered paper and board is also seeing an upward trend. There are already signs that there is a shortage of good quality recovered raw materials in certain parts of the world.
 Increasing raw material use and price, transport costs, and deteriorating raw material quality will all affect a mill’s productivity. Ultimately, design of the RCF line and its ability to handle a higher content of impurities will determine the future cost-effectiveness of the entire mill. Technological developments enable the use of lower grade furnishes, while producing final products with improved quality.
 Many mills all over the world have been investing recently and some are currently planning to invest in new industrial-grade lines. Many decisions are based on the current situation where, for example, it is possible to use 100% good quality OCC as raw material.
 The situation will change, however, in the future and this in turn influences mills in many ways. Lines must start using very high percentages of mixed waste. Some will even go up to 100% low quality mixed waste. The equipment chosen today dictates how well a new OCC/MW line will be able to cope with this wide range of raw materials in the future.
 In this paper, a very simple but also very effective solution is presented for a modern industrial-grade RCF line.
Results are also provided from several mill installations and pilot plant trials.
The main target is early removal of contaminant and a minimum of equipment to reach the required quality. The pulping stage is the first and most important stage of the line. Pulping will dictate the pulp properties, impurities content following pulping, and operation of the entire line.


Report of the 13 International Symposium on Wood, Fiber and Pulping Chemistry (13 ISWFPC)

Gyosuke Meshitsuka
The University of Tokyo

 13 International Symposium on Wood, Fiber and Pulping Chemistry (13 ISWFPC) was held at Sky City Convention Centre in Auckland, New Zealand as the joint symposium of 59th APPITA Annual Meeting. Main topics of this symposium are pulping and bleaching chemistry. About 200 papers including 99 oral papers were presented at 11 sessions of pulping and bleaching chemistry, cellulose chemistry, surface chemistry, biosynthesis and chemical structure and so on. Forty nine papers including 22 poster papers were in the field of pulping and bleaching chemistry, which were largest number among all sessions.


Optimum Design of Flute Structure for Edgewise Compression of Corrugated Fiberboard

Eiichi Mikami, Takamasa Ibaraki and Isao Kodaka
Pulp & Paper Research Laboratory, Oji Paper Co., Ltd.

 Corrugated containers are widely used for packaging various products. The compressive strength of corrugated fiberboard determines the compressive strength of the corrugated container, which is one of the most important required properties. To obtain higher compressive strength, various measures can be taken, such as raising the basis weight, adding more kraft pulp or using more fluting medium. However these measures generally increase the cost.
 Here we report the results of our study on flute structure with a view to improving the edgewise compression strength of corrugated fiberboard without increasing costs. Our method is to simulate the deformation behavior of an edgewise crush test (ECT) using finite element method (FEM). In our study, the compressive strength of corrugated fiberboard was estimated through the following procedure.
 Firstly, the compressive strengths (Sc) of the liner and the fluting medium were ascertained by carrying out short-span compression tests (SCTs). Next, these SCTs were simulated, then the maximum equivalent stress at the point at which the model reached Sc was regarded as the failure criterion. The compressive strength of the corrugated fiberboard was assumed to be equal to the reaction force at the point at which the liner or the fluting medium reached the failure criterion in the ECT simulation. In the FEM simulation, nonlinear structural analysis was carried out under the assumption that both the liner and the fluting medium behave as orthotropic elastic-plastic materials. The model of corrugated fiberboard was constructed of shell elements.
 On the other hand, a series of experimental corrugated fiberboards with various flute shapes (U-shape, V-shape, UV-shape and so on) were prepared, then their edgewise compression strengths were compared.
 As a result, the V-shape with the larger glue width was found to have the most advantageous flute structure in terms of strength and cost.

Keywords: Corrugated fiberboard, Finite element method, Flute structure, Edgewise compression
        strength, Edgewise crush test, Short-span compression test


Characteristic Mechanical Properties of Washi Papers

Tatsuo Yamauchi and Naoharu Usami
Graduate School of Agriculture, Kyoto University

 Comparing with commercial papers from wood pulp, Japanese traditional papers, washi from kozo fibers show the following features; Washi generally gives thin paper sheet relating to its low basis weight. Sheet density and elastic modulus of washi are low, showing poor fiber-fiber bonding. However in-plane mechanical properties of washi are superior to those of wood pulp papers, especially tear strength and folding endurance are enormously excellent。 On the other hand out-of-plane mechanical property such as peeling strength at paper failure is poor for washi.

Keywords: Density, Fiber-fiber bonding, Kozo fiber, Mechanical properties, Washi